Zinner et al. (2007) examined conflicting results in the genetic analysis of sportive lemurs in northwestern Madagascar, those within the range of what once was considered to be Lepilemur dorsalis. Since the type localities of L. dorsalis Gray, 1871 and L. grandidieri Forsyth Major, 1894, were both “Northwest Madagascar”, the proper name of one or two of the new species from the region (sahamalazensis, grewcocki, mittermeieri, tymlerachsoni) could be either of these two. The true "dorsalis", as such, had not been identified, and no attempt has been made to identify grandidieri, formerly a junior synonym of dorsalis. Genetic analysis of the holotypes of dorsalis and grandidieri is needed to resolve this. Zinner et al. (2007) indicated, therefore, that tymerlachsoni and/or mittermeieri might be junior synonyms.

This species is listed as Critically Endangered as it has been observed to have undergone a population reduction of ≥80% over the past 21 years (three generations, assuming a generation length of seven years) due primarily to continuing decline in area, extent and quality of habitat, and exploitation through unsustainable levels of hunting (e.g., Seiler et al. 2010, 2012). This cause has not ceased, and will to a large extent not be easily reversible. A future population reduction of ≥80% over a 21 year period is also suspected due to the same cause.

Furthermore, the area of occupancy ofL. sahamalazensis covers less than 10 km2. This geographic range is severely fragmented and undergoing continuing decline in extent of occurrence, area of occupancy and in quality of habitat of the remaining areas (Seiler et al. 2013a). The number of subpopulations and mature individuals is also known to be in decline.

Restricted to the Sahamalaza Peninsula. The precise range of this species is not known, but inferring from the biogeography of this area of Madagascar and from the distribution of the sympatric Eulemur flavifrons, the northern boundary of the range is likely to be the Andranomalaza (Maetsamalaza) River, the southern boundary the Maevarano River (Mittermeier et al. 2010). While the extent of occurrence (EOO) is estimated to be lesser than 1,425 km2, the area of occupancy (AOO) is highly restricted to less than 10 km2.

The three remaining forest blocks of the Sahamalaza Peninsula and their unique fauna are in grave danger of disappearing, despite having been under official protection since 2007. The forests are already extremely degraded and highly fragmented; nonetheless, bush fires and tree-felling are activities that are routinely pursued and accepted within the local society (Seiler et al. 2010, 2012). In 2010, the Ankarafa Forest measured only about 185 ha, divided into six fragments (10, 10, 13, 22, 30 and 100 ha; Seiler et al. 2010).

Olivieri et al. (2005) recorded an encounter rate of 4.17 individuals/km2 in the forest of Ankarafa.This high encounter rate could be due to recent loss of habitat, forcing all animals to concentrate in the few remaining forest fragments. Ruperti (2007) recorded a mean density of 280 individuals/km2 in Ankarafa. Most recent data on Lepilemur density (Seiler et al. 2013a) suggests densities ranging from only 7 to 23 individuals/km2in the same area. The differences between density estimations are most likely due to different methods of data collection. Whereas Ruperti measured lemur density inside one-hectare plots (one for each fragment), Seiler et al. counted all individuals found during 12 months of field work. Another factor that may have contributed to the differences is ongoing habitat alteration. During the study period from 2009 to 2011, various observations were made of illegal logging (often hardwoods), slash-and-burn agriculture and poaching of the sportive lemurs on the Sahamalaza Peninsula(Seiler et al. 2010, 2012).

The Sahamalaza Peninsula is part of a transition zone between the Sambirano region in the north and the western dry deciduous forest region in the south. The species inhabits both primary and mature secondary forests. Irrespective of the differences in overall structure and habitat parameters of the forest fragments in Ankarafa, the microhabitat in sportive lemurs’ home ranges as well as around sleeping sites was similar in all measured habitat parameters, as were all measured parameters for the different sleeping trees (Seiler et al. 2013b, 2014). Sahamalaza sportive lemurs chose the locations of their home ranges on the basis of different habitat variables, with abundance of sleeping sites and feeding trees as well as tree density and canopy cover being the most important factors (Seiler et al. 2014). Tall trees with large crowns, a high density of small trees, and dense canopy were particularly important for sleeping site choice (Seiler et al. 2013b).

The Sahamalaza sportive lemur is a highly folivorous generalist herbivore, who was observed to feed on at least 42 different tree species, preferring the abundant species Clitoria lasciva, Mangifera indica, Garcinia pauciflora and Sorindeia madagascariensis and occasionally adding fruits of Ficus tiliaefolia, spiders, insects and insect larvae to its diet. It had prolonged times of resting during its activity periods (Seiler et al. 2014). Home ranges covered an area of 1.4 h (nightly ranges of 0.5 ha) and did not overlap between adult individuals (Seiler 2012). The very few sociopositive interactions between individuals took place between mother and kin. Though the small number of observed individuals makes it hard to finally conclude on the social organization of the Sahamalza sportive lemur, the low level of social interaction and cohesiveness suggest that the Sahamalaza sportive lemur has a very low degree of social complexity and is likely to be solitary (Seiler 2012).

During daylight hours the Sahamalaza sportive lemur rested alone (except mother-infant pairs) in tree holes or in tree tangles (Seiler et al. 2013b). Tree holes used as sleeping sites were usually found in Bridelia pervilleana, whilst tree tangle sleeping sites are mostly located in Sorindeia madagascariensis. Individuals resting in tree holes usually sat at the entrance rather than inside the hole, possibly to increase sun exposure. During diurnal observations, 5-14 % of the sportive lemurs’ behavior was active, although the animals never leave their sleeping sites or feed. Comparing the proportion of active behavior between individuals resting in tree holes and those in tree tangles, animals in tree holes to have significantly higher levels of activity (Seiler et al. 2013b).

The species is hunted at increasingly high rates by the local human population since the onset of the political crisis in Madagascar in 2009, due to an almost complete lack of law enforcement. The level of hunting is likely to be unsustainable (Seiler et al. 2012).

Although some of the known distribution is within a protected area, forest clearing for agriculture, and timber-cutting for charcoal and construction continue at high rates, especially since the onset of the political crisis in Madagascar in 2009. The species is also subject to increasing levels of hunting (Seiler et al. 2012).

Listed on CITES Appendix I. The species is present in the Sahamalaza–Iles Radama National Park (Aire Protégée Terrestre, Marine et Côtière) which is part of the country's protected area network managed through Madagascar National Parks (MNP). The Sahamalaza Peninsula is also a UNESCO Biosphere Reserve (declared in 2001). The Association Européenne pour l'Etude et la Conservation des Lémuriens (AEECL), together with MNP and the local communities, is carrying out a community-based natural resource management programme to ensure a better protection of the very few remaining forest fragments in the park (Schwitzer et al. 2006). Further work is needed to clarify the exact distribution and taxonomic limits of the recently described Lepilemur species.